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Finasteride is a 5α-Reductase inhibitor. 5α-Reductase is the enzyme responsible for converting testosterone into dihydrotestosterone (DHT), a form of testosterone that is 100x more potent. It is commonly prescribed to cis males to treat enlarged prostate, slow the rate of male pattern baldness, and help decrease the risk of prostate cancer. It has also been found to reduce excessive facial and/or body hair growth (hirsutism) in cis women.
|Drug class:||5α-Reductase inhibitor, Antiandrogen|
|Dosage range:||Oral: 0.5–5 mg/day|
|Brand names:||Propecia, Proscar, Finpecia|
|Elimination half-life||Adults: 5–6 hours
Elderly: >8 hours
It is commonly prescribed to transgender women as an antiandrogen to block the synthesis of DHT, which could potentially lead to less or even reverse-feminization in certain cases. It's recommended that you consult a doctor before incorporating finasteride in your HRT regimen, as there are several negative side effects associated with the drug and may be unnecessary.
Method of Action
Finasteride is a selective inhibitor of type II and III isoforms of the enzyme 5α-Reductase. This reduces the creation of DHT from testosterone in hair follicles, skin, and the prostate gland anywhere between 60-90%. It will not completely block DHT's creation as it does not act upon 5α-Reductase type I isoenzyme. It's highly recommended that you use bicalutamide to assist in completely blocking the negative effects of DHT. If bicalutamide is not available, dutasteride has been found to reduce DHT levels in the entire body by more than 99%, but this medication comes with its own list of side effects.
Allopregnanolone and 3α-androstanediol
Allopregnanolone and 3α-androstanediol are both neurosteroids produced naturally with progesterone and DHT respectively. These activate the GABAA receptor in the brain. Finasteride inhibits the creation of neurosteroids and contributes to a reduction in GABAA, which has been known to lead to anxiety, depression, and sexual dysfunction.
The use of finasteride may result in the following side effects...
- Erectile dysfunction
- Loss of libido
- Ejaculatory disorders
- Reduction in penis size
- Reduced penis sensation
- Muscular atrophy
- Dry skin
- Cognitive impairments/brain fog
- Suicidal ideation
The usual dose recommended is 0.5 to 1 mg daily via oral administration. Doctors may prescribe up to 5 mg daily, but this may be more than is necessary depending on your hormone levels. Hormone levels, specifically DHT, should be monitored through blood tests to ensure you are receiving the appropriate dosages of finasteride.
Topical finasteride is also prescribed to treat pattern hair loss and has shown a decrease in serum DHT levels. However, serum DHT inhibition using this method is less effective than the oral route.
The major brand names of finasteride are Propecia (1 mg), commonly prescribed for hair loss, and Proscar (5 mg), for enlarged prostate. Other brand names used for finasteride are Finpecia or Fincar.
|Finalo 1mg x 10||3.65€||3.17€||UnitedPharmacies-NL||(NL-Centric)|
|Finalo 1mg x 10||3.31£||2.88£||UnitedPharmacies-UK||(UK-Centric)|
|Finast 5mg x 30||22.72$||20.45$||UnitedPharmacies||(US-Centric)|
|Finast 5mg x 30||20.57€||18.51€||UnitedPharmacies-NL||(NL-Centric)|
|Finast 5mg x 30||18.68£||16.81£||UnitedPharmacies-UK||(UK-Centric)|
|Finast 5mg x 30||12.40$||9.12$||WebOrderPharmacy||Ships from India|
|Finasteride 5mg x 30||11.95$||Pilloid||Ships from Russia|
|Finasteride 5mg x 30||11.95$||OTC-Online-Store||Ships from Russia|
|Finax 1mg x 30||9.20$||5.52$||WebOrderPharmacy||Ships from India|
|Fincar 5mg x 30||17.24$||14.90$||AllDayChemist||Various fulfillment centers|
|Finpecia 1mg x 10||4.23$||3.80$||UnitedPharmacies||(US-Centric)|
|Finpecia 1mg x 30||28.75$||16.50$||InHousePharmacy||Ships from Vanuatu|
|Finpecia 1mg x 30||7.60$||6.46$||AllDayChemist||Various fulfillment centers|
|Finpros 5mg x 100||62.78€||EU-Aibolit||Ships from EU|
|Novaride 5mg x 30||8.00$||Medicina Mexico||Ships from Mexico|
|Penester 5mg x 90||55.82€||EU-Aibolit||Ships from EU|
|Propecia 1mg x 28||87.85$||Amazon4Health||Ships from Thailand|
|Proscar 5mg x 28||31.30€||Aphrodite's||Ships from Portugal|
|Proscar 5mg x 28||30.00€||Shape Shifter||Ships from Turkey|
|Proscar 5mg x 30||99.95$||Amazon4Health||Ships from Thailand|
|Prosteride 5mg x 30||29.50$||24.84$||InHousePharmacy||Ships from Vanuatu|
Finasteride can be purchased in tablet form through a variety of sources such as online pharmacies. However, it can also be purchased in bulk powdered form through vendors on websites such as Alibaba. From personal experience, Alibaba is substantially cheaper and some vendors will often go to great lengths to get your product to you by deliberately mislabelling packages in order to more easily get them through customs. We have personally had good luck with this particular vendor. It is also worth noting that in order to purchase products from these sites, you will need to personally contact the vendor and negotiate a price with them.
- Finasteride (Drugs.com) | https://www.drugs.com/monograph/finasteride.html#moreResources
- An overview on 5α-reductase inhibitors (ScienceDirect.com) | https://doi.org/10.1016/j.steroids.2009.10.005
- Finn, D.A., Beadles‐Bohling, A.S., Beckley, E.H., Ford, M.M., Gililland, K.R., Gorin‐Meyer, R.E. and Wiren, K.M. (2006), A New Look at the 5α‐Reductase Inhibitor Finasteride. CNS Drug Reviews, 12: 53-76. doi:10.1111/j.1527-3458.2006.00053.x
- Römer, B. and Gass, P. (2010), Finasteride‐induced depression: new insights into possible pathomechanisms. Journal of Cosmetic Dermatology, 9: 331-332. doi:10.1111/j.1473-2165.2010.00533.x
- Gunn Benjamin, Brown Adam, Lambert Jeremy, Belelli Delia (2011). "Neurosteroids and GABAA Receptor Interactions: A Focus on Stress" 131. DOI=10.3389/fnins.2011.00131